The invention relates to a valve device mounted on a submersible pump for providing circulation in a waste water pump station.
As disclosed in U.S. Pat. No. 4,462,766, issued Jul. 31, 1984, sludge banks occur in waster water pump stations and other tanks in a sewage system due to poor circulation. Sludge banks can cause a number of problems including bad odors, risk of explosions, corrosion problems, etc.
This patent describes a solution which entails arranging a valve in the pump outlet, which is opened temporarily thus obtaining a circulation and flushing in the pump station. The sludge banks are dissolved and the fluid is homogenized.
In U.S. Pat. No. 4,948,342, issued Aug. 14, 1990, one inventive method and device are described for obtaining the circulation desired. In this patent, a bellows contains a sealingly connected diaphragm and valve cup, and a ball element within the diaphragm moves in dependence on the pressure situation in the valve.